At the time of the present patent application demand for increased data capacity and efficiency in Internet traffic continues to increase dramatically as more individuals and businesses increase their use of the Internet. The ever-increasing demand also drives development of equipment for use on the Internet such as data packet routers. A number of enterprises are now developing routers that are capable of faster and higher-capacity handling of data packets routed over the Internet.
The Internet, operating globally, comprises components from a wide variety of manufacturers. It is, of course, necessary that such equipment conform to certain hardware, software and connection standards, and operate by certain data transfer standards and protocols. These standards are all well-known to the skilled artisan.
As new and better equipment for routing data traffic in the Internet continues to be developed, researchers developing such equipment are endeavoring to include such as fault tolerance, diagnostic capabilities, and redundancy into the equipment, links between instances of routing equipment, and in implementation of routing protocols.
One of the important developments in Internet technology as of the time of filing of the present patent application is in development of faster and scalable routers utilizing a distributive-processor concept. The present inventors, for example, are involved in development of what are known in the art as Terabit routers, capable of much higher packet transfer rates than for routers currently available in the art. These routers are scalable to higher and higher overall data-transfer rates and capacity, by allowing upwards of seven thousand interfaces to network traffic.
An example of a Terabit router as known to the inventor comprises three types of processor-equipped cards adapted for controlling and routing data. Each card has it's own processor lending to a relatively newer concept of distributive-processor data routers. The three types of cards are control cards, line cards, and fabric cards. Generally speaking, a line card functions as an interface for the internal network of the router and the external network to which the router connects. Data packets entering and exiting the Terabit router typically do so through a line card. Fabric cards are a part of an internal data-routing fabric or network of the data router. Fabric cards act as individual routing points within the data router. Control cards are responsible for controlling both line and fabric cards in terms of their functions including initiating routing protocols, maintenance, special processing, control-message distribution, and so on.
In the prior art, most routers use a single processor for the processing of data packets. Some routers use more than one processor, however the number of processors is relatively small compared to a distributive data router as known to the inventor. When a data router of the prior art needs updating with new software such as newer versions of routing protocols, configuration software, or the like, the router being upgraded must be shut down and taken off line in order to perform the upgrade. After the upgrade is complete, the router must be re-booted to again join the network topology with its peers.
With efficiency of data routing in mind, it is clear that the loss of a router during upgrade procedures affects network performance through the particular portion of the network occupied by the router. Data must be re-routed through peer routers on to its destination, sometimes taking a much longer or even more constricted path or paths. It is desirable, however, that data packets be routed efficiently through a given network and connected routers at all times. Taking one or more routers down for upgrade can be a major inconvenience. The nature of a distributive router as known to the inventor provides processor architecture that may be treated differently than its single-processor counterparts where upgrading is concerned.
What is clearly needed is a method and apparatus for enabling a software upgrade to be applied to a distributive-processor data router without having to take the entire router off-line and without significant performance degradation during upgrade. A system such as this would enable, in most cases, automated upgrade of data routing protocol revisions, configuration changes and the like.